diff --git a/lisp/emacs-lisp/byte-run.el b/lisp/emacs-lisp/byte-run.el
index 84cc83f2270..f9e86d88806 100644
--- a/lisp/emacs-lisp/byte-run.el
+++ b/lisp/emacs-lisp/byte-run.el
@@ -218,7 +218,7 @@ So far, FUNCTION can only be a symbol, not a lambda expression."
               val)))))
 
 (defalias 'byte-run--set-function-type
-  #'(lambda (f _args &rest val)
+  #'(lambda (f _args val)
       (list 'function-put (list 'quote f)
             ''function-type (list 'quote val))))
 
diff --git a/lisp/emacs-lisp/comp-common.el b/lisp/emacs-lisp/comp-common.el
index ef40882a98a..355988838c7 100644
--- a/lisp/emacs-lisp/comp-common.el
+++ b/lisp/emacs-lisp/comp-common.el
@@ -517,7 +517,7 @@ itself."
       (when (and f (null type-spec))
         (if-let ((delc-type (function-get function 'function-type)))
             ;; Declared Lisp function
-            (setf type-spec (car delc-type))
+            (setf type-spec delc-type)
           (when (subr-native-elisp-p f)
             ;; Native compiled inferred
             (setf kind 'inferred
diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index b1e4b77ae40..e69de84362e 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -825,7 +825,7 @@ clashes."
             (comp-func-lap func) lap
             (comp-func-frame-size func) (comp--byte-frame-size byte-func)
             (comp-func-speed func) (comp--spill-speed name)
-            (comp-func-declared-type func) (car (comp--spill-decl-spec name 'function-type))
+            (comp-func-declared-type func) (comp--spill-decl-spec name 'function-type)
             (comp-func-pure func) (comp--spill-decl-spec name 'pure))
 
       ;; Store the c-name to have it retrievable from